Paracetamol poisoning and the kidney

Paracetamol overdose causing acute kidney injury without hepatotoxicity: a case report

BACKGROUND

Paracetamol is a widely used analgesic and antipyretic. Paracetamol-induced hepatotoxicity is well known, but nephrotoxicity without hepatotoxicity is rarely seen.

CASE PRESENTATION

We present a case of acute kidney injury without hepatotoxicity in paracetamol overdose. A 15-year-old girl was admitted 48 h after she had taken 10 g of paracetamol. She was complaining of abdominal pain and vomiting. Her blood level of creatinine was 1.20 mg/dL on admission, with a peak at 3.67 mg/dL 3 days later. The liver blood tests and blood paracetamol level were negative. She did not receive N-acetyl cysteine and was treated with intravenous fluid (crystalloid). The ultrasonography of the kidneys was normal. Her renal function returned almost to baseline 7 days after admission. It was concluded that the diagnosis was an acute kidney injury caused by acute tubular necrosis due to paracetamol overdose.

CONCLUSION

This case shows that nephrotoxicity can occur without hepatotoxicity in paracetamol overdose.

Lack of mitochondrial Cyp2E1 drives acetaminophen-induced ER stress-mediated apoptosis in mouse and human kidneys: Inhibition by 4-methylpyrazole but not N-acetylcysteine

Acetaminophen (APAP) overdose causes liver injury and acute liver failure, as well as acute kidney injury, which is not prevented by the clinical antidote N-acetyl-L-cysteine (NAC). The absence of therapeutics targeting APAP-induced nephrotoxicity is due to gaps in understanding the mechanisms of renal injury. APAP metabolism through Cyp2E1 drives cell death in both the liver and kidney. We demonstrate that Cyp2E1 is localized to the proximal tubular cells in mouse and human kidneys. Virtually all the Cyp2E1 in kidney cells is in the endoplasmic reticulum (ER), not in mitochondria. By contrast, hepatic Cyp2E1 is in both the ER and mitochondria of hepatocytes. Consistent with this subcellular localization, a dose of 600 mg/kg APAP in fasted C57BL/6J mice induced the formation of APAP protein adducts predominantly in mitochondria of hepatocytes, but the ER of the proximal tubular cells of the kidney. We found that reactive metabolite formation triggered ER stress-mediated activation of caspase-12 and apoptotic cell death in the kidney. While co-treatment with 4-methylpyrazole (4MP; fomepizole) or the caspase inhibitor Ac-DEVD-CHO prevented APAP-induced cleavage of procaspase-12 and apoptosis in the kidney, treatment with NAC had no effect. These mechanisms are clinically relevant because 4MP but not NAC also significantly attenuated APAP-induced apoptotic cell death in primary human kidney cells. We conclude that reactive metabolite formation by Cyp2E1 in the ER results in sustained ER stress that causes activation of procaspase-12, triggering apoptosis of proximal tubular cells, and that 4MP but not NAC may be an effective antidote against APAP-induced kidney injury.

Mitochondrial versus microsomal bioactivation of paracetamol by human liver and kidney tissues

Mitochondria appeared to be a major target for paracetamol (PAR)-induced hepatotoxicity. Studies suggested that microsomal CYPs catalyse bioactivation of PAR to N-acetyl-p-benzoquinone imine (NAPQI), which alkylates mitochondrial proteins, and causes transmission of death signal from mitochondria to nucleus. We hypothesised that local formation of NAPQI within mitochondria seems more likely compared to the translocation of NAPQI. We therefore tested whether the formation of NAPQI may be catalysed by mitochondrial CYPs. Cellular fractions were isolated from human liver and kidney to compare the metabolic capacities. Liver and kidney mitochondria are capable to generate NAPQI. Mitochondrial CYP2E1 and CYP3A4 activities were comparable to the microsomal counterparts in both organs. Previously reported higher kidney microsomal CYP2E1 activity in men compared women were observed in mitochondrial CYP2E1 as well in the present study. On the other hand, no correlation between kidney CYP2E1 activity and quantity of NAPQI formation, as well as no induction on mitochondrial permeability transition pore (mPTP) opening by PAR in kidney mitochondria strongly suggested a different toxicity mechanism in this organ.

Decision tree outcome prediction of acute acetaminophen exposure in the United States: A study of 30,000 cases from the National Poison Data System

Acetaminophen is one of the most commonly used analgesic drugs in the United States. However, the outcomes of acute acetaminophen overdose might be very serious in some cases. Therefore, prediction of the outcomes of acute acetaminophen exposure is crucial. This study is a 6-year retrospective cohort study using National Poison Data System (NPDS) data. A decision tree algorithm was used to determine the risk predictors of acetaminophen exposure. The decision tree model had an accuracy of 0.839, an accuracy of 0.836, a recall of 0.72, a specificity of 0.86 and an F1_score of 0.76 for the test group and an accuracy of 0.848, a recall of 0.85, a recall of 0.74, a specificity of 0.87 and an F1_score of 0.78 for the training group. Our results showed that elevated serum levels of liver enzymes, other liver function test abnormality, anorexia, acidosis, electrolyte abnormality, increased bilirubin, coagulopathy, abdominal pain, coma, increased anion gap, tachycardia and hypotension were the most important factors in determining the outcome of acute acetaminophen exposure. Therefore, the decision tree model is a reliable approach in determining the prognosis of acetaminophen exposure cases and can be used in an emergency room or during hospitalization.

Protective role of Chlorella vulgaris with Thiamine against Paracetamol induced toxic effects on haematological, biochemical, oxidative stress parameters and histopathological changes in Wistar rats

Paracetamol is extensively consumed as an analgesic and antipyretic drug, but at a high dose level, it leads to deleterious side effects, such as hepatic and nephrotoxicity. This research aimed to estimate the prophylactic efficacy of Chlorella vulgaris and/or thiamine against paracetamol (P) induced hepatorenal and cardiac toxicity. Forty-eight female Wistar rats were randomly divided into eight equal groups (n = 6 rats). Group 1, normal control group. Group 2, Paracetamol group. Groups 3, 4 and 5 were treated with Silymarin drug, Chlorella vulgaris alga, Chlorella vulgaris alga supplemented with thiamine, respectively daily for 7 successive days, then all were administered Paracetamol (2gm/kg. bwt.). While, Groups 6, 7 and 8 were treated by Silymarin, Chlorella vulgaris alga, Chlorella vulgaris supplemented with thiamine, respectively daily for 7 successive days without paracetamol administration. Our results clarified that Paracetamol toxicity caused significant adverse effects on hematological, serum biochemical parameters, and oxidant -antioxidant status as well as histopathological picture of heart, liver, and kidney. However, in the Paracetamol intoxicated groups pretreatment either with Chlorella vulgaris alone or plus thiamine successfully improved the undesirable deleterious effects of paracetamol, and restored almost all variables to near their control levels. This study has finished to that oxidative stress participates in the pathogenesis of paracetamol-induced toxicity in rats and using Chlorella vulgaris alga either alone or plus thiamine alongside their health benefits can protect against oxidative harmful effects induced by paracetamol through their free radical scavenging and powerful antioxidant effects, and they can be used as propylactic agents against paracetamol-induced toxicity.

Renoprotective effects of cinnamon oil against APAP-Induced nephrotoxicity by ameliorating oxidative stress, apoptosis and inflammation in rats

Acetaminophen (APAP) is used as a primary medication in relieving moderate pain and fever. However, APAP is associated with toxic effects in renal tissue that appear because of its free radicals property. The principle goal of the present work is to assess the kidney damage by APAP and its restore antioxidative property of cinnamon oil (CO). Animals were distributed into six animals each in six groups. Rats were administered with three varying doses of CO from 50 to 200 mg/kg b.w. respectively and only a single dose of APAP. APAP induced an alteration in serum biochemical markers, imbalance in oxidative parameters, morphological changes in kidney tissue along with increased interleukins cytokines (IL-1β & 6) and caspase (3, 9) levels. CO administration significantly ameliorates all the parameters and histopathological changes were restored. Moreover, it also restored the activities of antioxidative enzymes. Our work proved that an variance of oxidative markers in the kidney by APAP is ameliorated by CO in rats. Thus, CO could be used in reducing APAP-induced nephrotoxicity.

Transfer of hepatocellular microRNA regulates cytochrome P450 2E1 in renal tubular cells

BACKGROUND

Extracellular microRNAs enter kidney cells and modify gene expression. We used a Dicer-hepatocyte-specific microRNA conditional-knock-out (Dicer-CKO) mouse to investigate microRNA transfer from liver to kidney.

METHODS

Dicerflox/flox mice were treated with a Cre recombinase-expressing adenovirus (AAV8) to selectively inhibit hepatocyte microRNA production (Dicer-CKO). Organ microRNA expression was measured in health and following paracetamol toxicity. The functional consequence of hepatic microRNA transfer was determined by measuring the expression and activity of cytochrome P450 2E1 (target of the hepatocellular miR-122), and by measuring the effect of serum extracellular vesicles (ECVs) on proximal tubular cell injury. In humans with liver injury we measured microRNA expression in urinary ECVs. A murine model of myocardial infarction was used as a non-hepatic model of microRNA release.

FINDINGS

Dicer-CKO mice demonstrated a decrease in kidney miR-122 in the absence of other microRNA changes. During hepatotoxicity, miR-122 increased in kidney tubular cells; this was abolished in Dicer-CKO mice. Depletion of hepatocyte microRNA increased kidney cytochrome P450 2E1 expression and activity. Serum ECVs from mice with hepatotoxicity increased proximal tubular cell miR-122 and prevented cisplatin toxicity. miR-122 increased in urinary ECVs during human hepatotoxicity. Transfer of microRNA was not restricted to liver injury -miR-499 was released following cardiac injury and correlated with an increase in the kidney.

INTERPRETATION

Physiological transfer of functional microRNA to the kidney is increased by liver injury and this signalling represents a new paradigm for understanding the relationship between liver injury and renal function.

FUNDING

Kidney Research UK, Medical Research Scotland, Medical Research Council.

4-methylpyrazole protects against acetaminophen-induced acute kidney injury

Acetaminophen (APAP) hepatotoxicity is the most common cause of acute liver failure in the United States, and while a significant percentage of APAP overdose patients develop kidney injury, molecular mechanisms involved in APAP-induced nephrotoxicity are relatively unknown. We have shown that 4-methylpyrazole (4MP, Fomepizole) protects against APAP-induced liver injury by inhibiting reactive metabolite formation through Cyp2E1, and analysis of data from APAP overdose patients indicated that kidney dysfunction strongly correlated with severe liver injury. Since Cyp2E1 is also expressed in the kidney, this study explored protection by 4MP against APAP-induced nephrotoxicity. Male C57BL/6 J mice were treated with either 300 or 600 mg/kg APAP with or without 4MP for 2, 6 or 24 h, followed by measurement of APAP metabolism and tissue injury. Interestingly, levels of APAP and its non-oxidative metabolites were significantly higher in kidneys when compared to the liver. APAP-protein adducts were present in both tissues within 2 h, but were absent in kidney mitochondria, unlike in the liver. While GSH depletion was seen in both tissues, activation of c-jun N-terminal kinase and its translocation to the mitochondria, which is a critical feature of APAP-induced liver injury, was not detected in the kidney. Treatment with 4MP attenuated APAP oxidative metabolite generation, GSH depletion as well as kidney injury indicating its potential use in protection against APAP-induced nephrotoxicity. In conclusion, since reactive metabolite formation seems to be common in both liver and kidney, 4MP mediated inhibition of Cyp2E1 protects against APAP-induced nephrotoxicity. However, downstream mechanisms of APAP-induced nephrotoxicity seem distinct from the liver.

Effects of hydrogen sulfide on acetaminophen-induced acute renal toxicity in rats

INTRODUCTION AND AIM

Hydrogen sulfide (H₂S) is an endogenously produced gas-structure mediator. It is proposed to have antioxidant, anti-inflammatory and antiapoptotic effects. Acetaminophen (N-acetyl-P-aminophenol; APAP) is an antipyretic and analgesic medication known as paracetamol. When taken at therapeutic doses there are few side-effects, but at high doses APAP can cause clear liver and kidney damage in humans and experimental animals. In this study, the effects of the H₂S donor of sodium hydrosulfide (NaHS) on acute renal toxicity induced by APAP in rats were researched in comparison with N-acetyl cysteine (NAC).

METHOD

Rats were divided into six groups (n = 7) as control. APAP, APAP + NAC, APAP + NaHS 25 µmol/kg, NaHS 50 µmol/kg and NaHS 100 µmol/kg. After oral dose of 2 g/kg APAP, NAC and NaHS were administered via the i.p. route for 7 days. In renal homogenates, KIM-1 (Kidney Injury Molecule-1), NGAL (neutrophil gelatinase-associated lipocalin), TNF-α and TGFβ levels were measured with the ELISA method for tissue injury and inflammation. In renal tissue, oxidative stress levels were identified by spectrophotometric measurement of TAS and TOS. Histopathologic investigation of renal tissue used caspase 3 staining for apoptotic changes, Masson trichrome and H&E staining for variations occurring in glomerular and tubular systems.

RESULTS

NaHS lowered KIM-1, NGAL, TNF-α, TGF-β and TOS levels elevated in renal tissue linked to APAP and increased TAS values. NaHS prevented apoptosis in the kidney and was identified to ensure histologic amelioration in glomerular and tubular structures. NaHS at 50 µmol/kg dose was more effective, with the effect reduced with 100 µmol/kg dose.

CONCLUSION

H₂S shows protective effect against acute renal injury linked to APAP. This protective effect reduces with high doses of H₂S. The anti-inflammatory and antioxidant activity of H₂S may play a role in the renoprotective effect.

Inter-individual and inter-organ variability in the bioactivation of paracetamol by human liver and kidney tissues

Paracetamol (PAR) overdose is associated with massive hepatic injury; it may induce kidney toxicity as well. It is essential to measure organ-specific activities of related CYPs for evaluating the overdose cases. Available HPLC-based methods require high amounts of tissue samples. In order to develop liquid chromatography mass spectrometry (LC-MS)-based methods to process small amounts of human tissues, liver and kidney samples were obtained. Individual microsomes were prepared and incubated with PAR (for quantifying bioactivation), with nifedipine (for measuring CYP3A4 activity) and with p-nitrophenol (for measuring CYP2E1 activity). The small amount of tissue microsomes was sufficient to measure both the formation of NAPQI and the activities of CYP enzymes. Although the sample size in group was relatively low, both NAPQI formation and activity of CYP2E1 were significantly higher in males compared to females in kidney. Considerable variations in the metabolic capacity of individuals were observed for both organs.

Paracetamol: overdose-induced oxidative stress toxicity, metabolism, and protective effects of various compounds in vivo and in vitro

Paracetamol (APAP) is one of the most widely used and popular over-the-counter analgesic and antipyretic drugs in the world when used at therapeutic doses. APAP overdose can cause severe liver injury, liver necrosis and kidney damage in human beings and animals. Many studies indicate that oxidative stress is involved in the various toxicities associated with APAP, and various antioxidants were evaluated to investigate their protective roles against APAP-induced liver and kidney toxicities. To date, almost no review has addressed the APAP toxicity in relation to oxidative stress. This review updates the research conducted over the past decades into the production of reactive oxygen species (ROS), reactive nitrogen species (RNS), and oxidative stress as a result of APAP treatments, and ultimately their correlation with the toxicity and metabolism of APAP. The metabolism of APAP involves various CYP450 enzymes, through which oxidative stress might occur, and such metabolic factors are reviewed within. The therapeutics of a variety of compounds against APAP-induced organ damage based on their anti-oxidative effects is also discussed, in order to further understand the role of oxidative stress in APAP-induced toxicity. This review will throw new light on the critical roles of oxidative stress in APAP-induced toxicity, as well as on the contradictions and blind spots that still exist in the understanding of APAP toxicity, the cellular effects in terms of organ injury and cell signaling pathways, and finally strategies to help remedy such against oxidative damage.

A monkey model of acetaminophen-induced hepatotoxicity; phenotypic similarity to human

Species-specific differences in the hepatotoxicity of acetaminophen (APAP) have been shown. To establish a monkey model of APAP-induced hepatotoxicity, which has not been previously reported, APAP at doses up to 2,000 mg/kg was administered orally to fasting male and female cynomolgus monkeys (n = 3-5/group) pretreated intravenously with or without 300 mg/kg of the glutathione biosynthesis inhibitor, L-buthionine-(S,R)-sulfoximine (BSO). In all the animals, APAP at 2,000 mg/kg with BSO but not without BSO induced hepatotoxicity, which was characterized histopathologically by centrilobular necrosis and vacuolation of hepatocytes. Plasma levels of APAP and its reactive metabolite N-acethyl-p-benzoquinone imine (NAPQI) increased 4 to 7 hr after the APAP treatment. The mean C_max level of APAP at 2,000 mg/kg with BSO was approximately 200 µg/mL, which was comparable to high-risk cutoff value of the Rumack-Matthew nomogram. Interestingly, plasma alanine aminotransferase (ALT) did not change until 7 hr and increased 24 hr or later after the APAP treatment, indicating that this phenotypic outcome was similar to that in humans. In addition, circulating liver-specific miR-122 and miR-192 levels also increased 24 hr or later compared with ALT, suggesting that circulating miR-122 and miR-192 may serve as potential biomarkers to detect hepatotoxicity in cynomolgus monkeys. These results suggest that the hepatotoxicity induced by APAP in the monkey model shown here was translatable to humans in terms of toxicokinetics and its toxic nature, and this model would be useful to investigate mechanisms of drug-induced liver injury and also potential translational biomarkers in humans.

The 100 most influential publications in paracetamol poisoning treatment: a bibliometric analysis of human studies

BACKGROUND

Analysis of the most influential publications within paracetamol poisoning treatment can be helpful in recognizing main and novel treatment issues within the field of toxicology. The current study was performed to recognize and describe the most highly cited articles related to paracetamol poisoning treatment.

METHODS

The 100 most highly cited articles in paracetamol poisoning treatment were identified from the Scopus database in November 2015. All eligible articles were read for basic information, including total number of citations, average citations per year, authors' names, journal name, impact factors, document types and countries of authors of publications.

RESULTS

The median number of citations was 75 (interquartile range 56-137). These publications were published between 1974 and 2013. The average number of years since publication was 17.6 years, and 45 of the publications were from the 2000s. A significant, modest positive correlation was found between years since publication and the number of citations among the top 100 cited articles (r = 0.316; p = 0.001). A total of 55 journals published these 100 most cited articles. Nine documents were published in Clinical Toxicology, whereas eight documents were published in Annals of Emergency Medicine. Citations per year since publication for the top 100 most-cited articles ranged from 1.5 to 42.6 and had a mean of 8.5 citations per year and a median of 5.9 with an interquartile range of 3.75-10.35. In relation to the origin of the research publications, they were from 8 countries. The USA had the largest number of articles, 47, followed by the UK and Australia with 38 and nine articles respectively.

CONCLUSIONS

This study is the first bibliometric assessment of the top 100 cited articles in toxicology literature. Interest in paracetamol poisoning as a serious clinical problem continues to grow. Research published in high-impact journals and from high income countries is most likely to be cited in published paracetamol research.

Incidence and characterization of acute kidney injury after acetaminophen overdose

PURPOSE

Acute kidney injury (AKI) occurs in 2-10% of patients with acetaminophen (APAP) overdose. Elevation in creatinine (SCr) typically occurs 2 to 5 days after ingestion, with a mean peak on day 7, and normalization over a month. However, it remains unclear whether renal impairment occurs without hepatotoxicity. We hypothesized that APAP-associated acute renal failure occurs in patients with and without severe liver dysfunction after APAP overdose.

MATERIALS AND METHODS

We retrospectively evaluated all patients admitted to the Medical Intensive Care Unit at a tertiary hospital and received acetylcysteine between June 2009 and December 2014. Of the 303 patients meeting these criteria, 139 of these patients received acetylcysteine for APAP overdose. Of these patients, 138 had Model for End-Stage Liver Disease (MELD) Scores on Day 1 of admission. Using a modified MELD (m-MELD) score, only containing total bilirubin and international normalized ratio not the SCr, the median m-MELD score was calculated. Patients with m-MELD scores below the median were compared to those with scores above the median (low m-MELD score <2.9 or high m-MELD score >2.9).

RESULTS

Baseline demographics were similar in the two groups with the exception of more hypertension in the low m-MELD group (24 vs 7%; P= .02). Time to admission was shorter in the low m-MELD group (7.9 ± 9.3 vs. 25.7 ± 29.2 hours; P= .001). The mean admission APAP level was 96.9 (±119) μg/mL in the low compared to 52.3 (±85.3) μg/mL in the high m-MELD group (P= .012). Day one SCr (1.2 ± 0.9 vs 2.7 ± 2.2 mg/dL; P< .0001) and change from baseline to highest SCr (0.2 ± 0.3 vs. 2.7 ± 3.3 mg/dL; P< .0001) were both lower in the low m-MELD group compared to the high m-MELD group. In addition, renal failure resolved upon discharge in all 2 patients (3%) with AKI in the low m-MELD group as compared to only 19 patients (44%) in the high m-MELD group.

CONCLUSIONS

Mean day one SCr, maximum change in SCr, and lack of renal failure resolution were higher in patients with higher m-MELD scores. However, patients with low m-MELD scores presented much earlier than patients with high m-MELD scores and 26% developed AKI.

The protective effects of aqueous extract of Carica papaya seeds in paracetamol induced nephrotoxicity in male wistar rats

BACKGROUND

Oxidative stress plays a crucial role in the development of drug induced nephrotoxicity. The study aimed to determine the nephroprotective and ameliorative effects of Carica papaya seed extract in paracetamol-induced nephrotoxicity in rats.

OBJECTIVES

To carry out phytochemical screening of Carica papaya, measure serum urea, creatinine and uric acid and describe the histopathological status of the kidneys in the treated and untreated groups.

METHODS

Phytochemical screening of the extract was done. Thirty two adult male Wistar rats were divided into four groups (n= 8 in each group). Group A (control) animals received normal saline for seven days, group B (paracetamol group) received normal saline, and paracetamol single dose on the 8th day. Group C received Carica papaya extract (CPE) 500 mg/kg, and paracetamol on the 8th day, while group D, rats were pretreated with CPE 750 mg/kg/day,and paracetamol administration on the 8th day. Samples of kidney tissue were removed for histopathological examination.

RESULTS

Screening of Carica papaya showed presence of nephroprotective pytochemicals. Paracetamol administration resulted in significant elevation of renal function markers. CPE ameliorated the effect of paracetamol by reducing the markers as well as reversing the paracetamol-induced changes in kidney architecture.

CONCLUSION

Carica papaya contains nephroprotective phytochemicals and may be useful in preventing kidney damage induced by paracetamol.

Drug-induced impairment of renal function

Pharmaceutical agents provide diagnostic and therapeutic utility that are central to patient care. However, all agents also carry adverse drug effect profiles. While most of these are clinically insignificant, some drugs may cause unacceptable toxicity that impacts negatively on patient morbidity and mortality. Recognizing adverse effects is important for administering appropriate drug doses, instituting preventive strategies, and withdrawing the offending agent due to toxicity. In the present article, we will review those drugs that are associated with impaired renal function. By focusing on pharmaceutical agents that are currently in clinical practice, we will provide an overview of nephrotoxic drugs that a treating physician is most likely to encounter. In doing so, we will summarize risk factors for nephrotoxicity, describe clinical manifestations, and address preventive and treatment strategies.

Protective Effect of Sundarban Honey against Acetaminophen-Induced Acute Hepatonephrotoxicity in Rats

Honey, a supersaturated natural product of honey bees, contains complex compounds with antioxidant properties and therefore has a wide a range of applications in both traditional and modern medicine. In the present study, the protective effects of Sundarban honey from Bangladesh against acetaminophen- (APAP-) induced hepatotoxicity and nephrotoxicity in experimental rats were investigated. Adult male Wistar rats were pretreated with honey (5 g/kg) for 4 weeks, followed by the induction of hepatotoxicity and nephrotoxicity via the oral administration of a single dose of APAP (2 g/kg). Organ damage was confirmed by measuring the elevation of serum alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), total protein (TP), total bilirubin (TB), urea, creatinine, and malondialdehyde (MDA). Histopathological alterations observed in the livers and the kidneys further confirmed oxidative damage to these tissues. Animals pretreated with Sundarban honey showed significantly markedly reduced levels of all of the investigated parameters. In addition, Sundarban honey ameliorated the altered hepatic and renal morphology in APAP-treated rats. Overall, our findings indicate that Sundarban honey protects against APAP-induced acute hepatic and renal damage, which could be attributed to the honey's antioxidant properties.

Therapeutic potential of different commercially available synbiotic on acetaminophen-induced uremic rats

BACKGROUND

Currently kidney disease appears a foremost problem across the world. Acetaminophen is a commonly used antipyretic agent, which in high doses, causes uremia and used for experimentally induction of kidney disease. Bacteriotherapy affords a promising approach to mitigate uremic toxins by ingestion of urease positive bacteria, probiotics and symbiotic able to catabolize uremic solutes within the gut. The present study evaluates the effect of seven commercial symbiotic on kidney disease.

METHODS

Fifty-four albino male rats were randomly divided into nine groups. Control group (Group-I) received distilled water interperitoneally for 7 days. Positive control group (Group-II) received 500 mg/kg acetaminophen interperitoneally for 7 days. Commercially available seven symbiotic combinations at a dose of 10(9)cells/day for 3 weeks was administered to the tested groups (Group III-IX) after receiving 500 mg/kg/day acetaminophen interperitoneally for 7 days. Blood, kidney, liver and stool samples were collected after scarification for biochemical tests and DNA fragmentation assay of kidney tissue, kidney histological studies. Limited fecal analysis was conducted.

RESULT

Blood urea nitrogen and toxicity indicators were increased, and antioxidant enzymes were decreased in Group-II. Blood urea nitrogen, toxicity indicators, glomerular necrosis, DNA damage of kidney tissue were reduced, and antioxidant enzymes were increased significantly in the treated Groups IV and IX (p < 0.05) in response to Group-II. Number of pathogenic bacteria decreased in synbiotic treated groups than Group I and II.

CONCLUSION

The study demonstrated that some of commercial symbiotic combination can reduce the sever effect of kidney disease.

An update on oxidative stress-mediated organ pathophysiology

Exposure to environmental pollutants and drugs can result in pathophysiological situations in the body. Research in this area is essential as the knowledge on cellular survival and death would help in designing effective therapeutic strategies that are needed for the maintenance of the normal physiological functions of the body. In this regard, naturally occurring bio-molecules can be considered as potential therapeutic targets as they are normally available in commonly consumed foodstuffs and are thought to have minimum side effects. This review article describes the detailed mechanisms of oxidative stress-mediated organ pathophysiology and the ultimate fate of the cells either to survive or to undergo necrotic or apoptotic death. The mechanisms underlying the beneficial role of a number of naturally occurring bioactive molecules in oxidative stress-mediated organ pathophysiology have also been included in the review. The review provides useful information about the recent progress in understanding the mechanism(s) of various types of organ pathophysiology, the complex cross-talk between these pathways, as well as their modulation in stressed conditions. Additionally, it suggests possible therapeutic applications of a number of naturally occurring bioactive molecules in conditions involving oxidative stress.

[Acetaminophen (paracetamol) causing renal failure: report on 3 pediatric cases]

Renal failure secondary to acetaminophen poisoning is rare and occurs in approximately 1-2 % of patients with acetaminophen overdose. The pathophysiology is still being debated, and renal acetaminophen toxicity consists of acute tubular necrosis, without complication if treated promptly. Renal involvement can sometimes occur without prior liver disease, and early renal manifestations usually occur between the 2nd and 7th day after the acute acetaminophen poisoning. While therapy is exclusively symptomatic, sometimes serious metabolic complications can be observed. The monitoring of renal function should therefore be considered as an integral part of the management of children with acute, severe acetaminophen intoxication. We report 3 cases of adolescents who presented with acute renal failure as a result of voluntary drug intoxication with acetaminophen. One of these 3 girls developed severe renal injury without elevated hepatic transaminases. None of the 3 girls' renal function required hemodialysis, but one of the 3 patients had metabolic complications after her acetaminophen poisoning.

Mechanism of the protective action of taurine in toxin and drug induced organ pathophysiology and diabetic complications: a review

Taurine (2-aminoethanesulfonic acid), a conditionally essential amino acid, is found in large concentrations in all mammalian tissues and is particularly abundant in aquatic foods. Taurine exhibits membrane stabilizing, osmoregulatory and cytoprotective effects, antioxidative properties, regulates intracellular Ca(2+) concentration, modulates ion movement and neurotransmitters, reduce the levels of pro-inflammatory cytokines in various organs and controls blood pressure. Recently, emerging evidence from the literature shows the effectiveness of taurine as a protective agent against several environmental toxins and drug-induced multiple organ injuries as the outcome of hepatotoxicity, nephrotoxicity, neurotoxicity, testicular toxicity and cardiotoxicity in several animal models. Besides, taurine is also effective in combating diabetes and its associated complications, including cardiomyopathy, nephropathy, neuropathy, retinopathy and atherosclerosis. These beneficial effects appear to be due to the multiple actions of taurine on cellular functions. This review summarizes the mechanism of the prophylactic role of taurine against several environmental toxins and drug-induced organ pathophysiology and diabetes.

Attenuation of uremia by orally feeding alpha-lipoic acid on acetaminophen induced uremic rats

Uremia means excess nitrogenous waste products in the blood & their toxic effects. An acute acetaminophen (paracetamol, N-acetyl p-aminophenol; APAP) overdose may result into potentially fatal hepatic and renal necrosis in humans and experimental animals. The aims of this present study were to investigate the protective effect of alpha-lipoic acid (ALA) on oxidative stress & uremia on male albino rats induced by acetaminophen. The study was performed by 24 albino male Wister strain rats which were randomly divided into four groups: Group I, control - receives normal food and water, Groups II, III & IV receive acetaminophen interperitoneally at the dose of 500 mg/kg/day for 10 days, from 11th day Groups III & IV were treated with ALA at the dose of 5 mg & 10 mg/100 g/day for 15 days, respectively. After 25 days of treatment, it was observed that there was a significant increase in plasma urea, creatinine, sodium and malondialdehyde (MDA) levels (p < 0.05) but a significant decrease in super oxide dismutase (SOD) & catalase activity & potassium level in uremic group is compared with control group & there was a significant increase in SOD & catalase (p < 0.05) & a significant decrease in serum urea, creatinine & Na and MDA (p < 0.05) in Group III & Group IV is compared with Group II & significant changes were observed in high ALA dose group. In conclusion it was observed that the ALA has nephroprotective activities by biochemical observations against acetaminophen induced uremic rats.

Toxicology in the ICU: Part 2: specific toxins

This is the second of a three-part series that reviews the generalized care of poisoned patients in the ICU. This article focuses on specific agents grouped into categories, including analgesics, anticoagulants, cardiovascular drugs, dissociative agents, carbon monoxide, cyanide, methemoglobinemia, cholinergic agents, psychoactive medications, sedative-hypnotics, amphetamine-like drugs, toxic alcohols, and withdrawal states. The first article discussed the general approach to the toxicology patient, including laboratory testing; the third article will cover natural toxins.

Hesperidin alleviates acetaminophen induced toxicity in Wistar rats by abrogation of oxidative stress, apoptosis and inflammation

Acetaminophen (APAP) is a widely used analgesic and antipyretic drug, but at high dose it leads to undesirable side effects, such as hepatotoxicity and nephrotoxicity. The present study demonstrates the comparative hepatoprotective and nephroprotective activity of hesperidin (HD), a naturally occurring bioflavonoid against APAP induced toxicity. APAP induces hepatotoxicity and nephrotoxicity as was evident by abnormal deviation in the levels of antioxidant enzymes. Moreover, APAP induced renal damage by inducing apoptotic death and inflammation in renal tubular cells, manifested by an increase in the expression of caspase-3, caspase-9, NFkB, iNOS, Kim-1 and decrease in Bcl-2 expression. These results were further supported by the histopathological examination of kidney. All these features of APAP toxicity were reversed by the co-administration of HD. Therefore, our study favors the view that HD may be a useful modulator in alleviating APAP induced oxidative stress and toxicity.

Impact of serum acetaminophen concentration on changes in serum potassium, creatinine and urea concentrations among patients with acetaminophen overdose

BACKGROUND

Acetaminophen overdose may be accompanied by electrolyte disturbances. The basis for electrolyte change appears to be due to increased fractional urinary electrolyte excretion.

PURPOSE

This study investigated the impact of serum acetaminophen concentration on changes in serum potassium, creatinine and urea concentrations in patients with acetaminophen overdose.

METHODS

This was a retrospective cohort study which included patients admitted to the emergency department and hospital within 24 h of acetaminophen ingestion. The study was conducted over a period of 5 years from 1 January 2004 to 31 December 2008. Data are presented as mean ± SD and as medians (interquartile range) and groups were compared using independent two-tailed Student t-test. Statistical Package for Social Sciences (SPSS) 15 was used for data analysis.

RESULTS

Two hundred and eighty-three patients were studied (44 males and 239 females), mean age 23 ± 7.5 years. Patients who had a serum acetaminophen concentration above a 'possible toxicity' treatment line were associated with an elevation in serum creatinine concentration (p=0.044) and a reduction in the serum potassium concentration (p<0.001) but were not associated with a reduction in serum urea concentration (p>0.99). During the study period, 63.3% (179 patients) had serum potassium concentrations less than the normal concentration (3.5 mmol/l) and 31.4% (89 patients) had serum urea concentrations less than the normal concentration (2.5 mmol/l). The serum creatinine concentration in all patients was within the normal range.

CONCLUSIONS

Acetaminophen appears to cause a concentration-dependent reduction of potassium concentrations and an elevation of creatinine concentrations of short duration (<24 h) after overdose.

Effects of acetaminophen on reactive oxygen species and nitric oxide redox signaling in kidney of arsenic-exposed rats

We examined whether acetaminophen could alter renal oxidative stress induced by arsenic; also whether withdrawal of acetaminophen treatment can increase susceptibility of kidney to arsenic toxicity. Acetaminophen (400 and 1600 mg/kg) was co-administered orally to rats for 3 days after preexposure to arsenic (25 ppm) for 28 days (Phase-I) and thereafter, acetaminophen was withdrawn, but arsenic exposure was continued for another 28 days (Phase-II). Acetaminophen enhanced arsenic-induced lipid peroxidation, GSH depletion and ROS production and further decreased superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities. Increased peroxidation did not alter kidney weight, but increased serum urea nitrogen and creatinine. Arsenic did not alter basal, iNOS-mediated NO production or iNOS expression. Arsenic decreased cNOS-mediated NO release and eNOS expression in Phase-II. Acetaminophen increased their expressions and NO production in Phase-I. In Phase-II, arsenic-mediated effects on NO remained mostly unaffected with acetaminophen. Results reveal that acetaminophen enhanced the risk of arsenic-mediated oxidative stress in kidney. Discontinuation of acetaminophen administration also increased the susceptibility of kidney to nephrotoxic effect of arsenic. It appeared ROS were primarily responsible for oxidative stress in both the phases. NO may have a minor role in Phase-I, but does not contribute to redox signaling mechanism in Phase-II.

Acetaminophen induces apoptosis in rat cortical neurons

Background

Acetaminophen (AAP) is widely prescribed for treatment of mild pain and fever in western countries. It is generally considered a safe drug and the most frequently reported adverse effect associated with acetaminophen is hepatotoxicity, which generally occurs after acute overdose. During AAP overdose, encephalopathy might develop and contribute to morbidity and mortality. Our hypothesis is that AAP causes direct neuronal toxicity contributing to the general AAP toxicity syndrome.

Methodology/Principal Findings

We report that AAP causes direct toxicity on rat cortical neurons both in vitro and in vivo as measured by LDH release. We have found that AAP causes concentration-dependent neuronal death in vitro at concentrations (1 and 2 mM) that are reached in human plasma during AAP overdose, and that are also reached in the cerebrospinal fluid of rats for 3 hours following i.p injection of AAP doses (250 and 500 mg/Kg) that are below those required to induce acute hepatic failure in rats. AAP also increases both neuronal cytochrome P450 isoform CYP2E1 enzymatic activity and protein levels as determined by Western blot, leading to neuronal death through mitochondrial–mediated mechanisms that involve cytochrome c release and caspase 3 activation. In addition, in vivo experiments show that i.p. AAP (250 and 500 mg/Kg) injection induces neuronal death in the rat cortex as measured by TUNEL, validating the in vitro data.

Conclusions/Significance

The data presented here establish, for the first time, a direct neurotoxic action by AAP both in vivo and in vitro in rats at doses below those required to produce hepatotoxicity and suggest that this neurotoxicity might be involved in the general toxic syndrome observed during patient APP overdose and, possibly, also when AAP doses in the upper dosing schedule are used, especially if other risk factors (moderate drinking, fasting, nutritional impairment) are present.

Effects of medical ozone therapy on acetaminophen-induced nephrotoxicity in rats

Acetaminophen (APAP), also known as paracetamol, is the commonest cause of toxic ingestion in the world. Because overdose of APAP has life-threatening effects on kidney, treatment of APAP-induced nephrotoxicity has life-saving importance. Aim of the study was to evaluate the efficacy of medical ozone therapy in experimental model of APAP toxication. Twenty-one male Wistar rats (200-250 g) were randomly assigned into three groups containing seven rats each: Sham, control (only APAP treated), and APAP + ozone therapy groups. Rats were killed 48 hours after administration of APAP. Urea, creatinine levels in the blood, and malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity in renal tissue were measured. Kidney tissues were stained with hematoxylin and eosin for histological assessment. APAP administration deteriorated the renal functions and significantly elevated renal MDA levels and depleted SOD and GSH-Px activities. Ozone therapy significantly reduced the MDA level, increased the SOD and GSH-Px activities, and normalized the renal histology. In conclusion, our study results are consistent with encouraging data for ozone therapy on APAP-induced nephrotoxicity in rats by improving antioxidant mechanism and oxidative stress.

Taurine protects acetaminophen-induced oxidative damage in mice kidney through APAP urinary excretion and CYP2E1 inactivation

Acute exposure of acetaminophen (APAP), a widely used analgesic and antipyretic drug, causes severe renal damage and no specific agent has been reported so far that plays any beneficial role in this organ pathophysiology. In the present study, the protective role of taurine on APAP-induced nephrotoxicity was investigated in mice. In order to induce acute nephrotoxicity, APAP was administered at a single dose of 2g/kg body weight orally to male adult albino mice of Swiss strain. APAP exposure for 24h significantly increased plasma level of blood urea nitrogen (BUN), creatinine, uric acid, TNF-alpha, NO production, urinary gamma-glutamyl transpeptidase (gamma-GT) activity, total urinary protein and urinary glucose level accompanied by a decrease in Na(+)-K(+)-ATPase activity. Moreover, APAP administration significantly increased MDA, protein carbonylation, GSSG level, intracellular ROS production and cytochrome P450 enzyme (CYPP450) activity. The same exposure decreased GSH level, ferric reducing/antioxidant power (FRAP) as well as the activities of antioxidant enzymes indicating that APAP-induced renal damage was mediated through oxidative stress. Besides, APAP exposure significantly reduced mitochondrial membrane potential and induced up-regulation of CYP2E1 in renal tissues although JNK did not play any significant role in this APAP-induced renal pathophysiology. Caspase 9/3 immunoblot and DNA fragmentation analyses showed that APAP-induced renal cell damage was mostly necrotic in nature, although some apoptosis also occurred simultaneously. Taurine treatment both pre and post (150 mg/kg body weight for 3 days, orally) to APAP exposure, however, significantly reduced APAP-induced nephrotoxicity through its antioxidant properties, urinary excretion of APAP and suppression of CYP2E1. Results suggest that taurine might be a potential therapeutic candidate against APAP-induced acute nephrotoxicity.

Acetaminophen induced renal injury via oxidative stress and TNF-alpha production: therapeutic potential of arjunolic acid

Acetaminophen (APAP) causes acute and chronic renal failure. The mechanisms leading to hepatic injury have been extensively studied, but the molecular mechanisms regarding APAP-induced nephro-toxicity are poorly defined. In earlier studies, we have demonstrated that arjunolic acid (AA) possesses protective roles against chemically induced organ pathophysiology. The purpose of the present study was to explore whether AA plays any protective role against APAP induced acute renal toxicity; and if so, what pathways it utilizes for the mechanism of its protective action. Exposure of rats with a nephro-toxic dose of APAP altered a number of biomarkers (like blood urea nitrogen and serum creatinine levels, etc.) related to renal oxidative stress, decreased antioxidant activity, elevated renal tumor necrosis factor-alpha and nitric oxide levels. AA treatment both pre- and post to APAP exposure protected the alteration of these biomarkers, compensated deficits in the antioxidant defense mechanisms, and suppressed lipid peroxidation in renal tissue. Investigating the inherent molecular signaling of this pathophysiology and its protection, we found that the mitochondrial pathway was not activated during APAP-induced cell death as no dissipation of mitochondrial membrane potential or release of cytochrome C was detected in the respective experiments. Our experimental evidence suggests that APAP-induced nephro-toxicity is a caspase-dependent process that involves activation of caspase-9 and caspase-3 in the absence of cytosolic cytochrome C release. These results provide evidence that inhibition of NO overproduction and maintenance of intracellular antioxidant status may play a pivotal role in the protective effects of AA against APAP-induced renal damage. AA represents a potential therapeutic option to protect renal tissue from the detrimental effects of acute acetaminophen overdose.

Delayed onset of acute renal failure after significant paracetamol overdose: A case series

Acute renal failure is a recognized manifestation of paracetamol toxicity, but comparatively little data is available concerning its onset and duration. The present study sought to characterize the time course of rising serum creatinine concentrations in paracetamol nephrotoxicity. Renal failure was defined by serum creatinine concentration ≥150 μmol/L (1.69 mg/dL) or ≥50% increase from baseline. Serum creatinine concentrations and alanine aminotransferase activity were considered with respect to the interval after paracetamol ingestion. There were 2068 patients with paracetamol overdose between March 2005 and October 2007, and paracetamol nephrotoxicity occurred in 8 (0.4%). All had significant hepatotoxicity, and peak serum alanine aminotransferase activity occurred at 2.5 days (2.2 to 2.9 days) after ingestion. Peak serum creatinine concentrations did not occur until 5.5 days (4.4 to 5.9 days) after ingestion (p = .031 by Wilcoxon test). Serum creatinine concentrations slowly restored to normal, and renal replacement was not required. In this patient series, rising serum creatinine concentrations only became detectable after more than 48 hours after paracetamol ingestion. Therefore, renal failure might easily be missed if patients are discharged home before this. Further work is required to establish the prevalence of paracetamol-induced nephrotoxicity, and its clinical significance.

[Acute renal failure after acetaminophen poisoning: report of three cases]

PURPOSE

Management of acetaminophen overdose focuses on the risk hepatic failure. However, acute renal failure, although less frequent, can lead to serious metabolic complications and require hemodialysis. We report three cases of acute renal failure related to acetaminophen overdose.

CLINICAL FEATURES

Three patients, aged 17-46 yr ingested acetaminophen 19 to 32 g, and were admitted to the intensive care unit because of acute liver failure without hepatic coma. While liver function improved, each patient developed acute renal failure starting on the fourth day. Four sessions of hemodialysis were required in one patient because of anuria. Hepatic function improved from the fourth to the ninth day in each case, whereas renal function recovered later, 10-20 days after ingestion. Investigations were negative for other causes of renal failure, and acute tubular necrosis due to acetaminophen was suspected.

CONCLUSION

The pathophysiology of this type of acute tubular necrosis remains unclear and thus, there is no specific treatment. Nevertheless, in all cases of acetaminophen overdose, we suggest following serum creatinine levels during the first week, regardless of the degree hepatic failure or quantity of acetaminophen ingested.

Therapeutic potential of hemin in acetaminophen nephrotoxicity in rats

The therapeutic potential of hemin, the heme oxygenase-1 inducer, was investigated against renal damage induced by acute acetaminophen overdose in rats. Nephrotoxicity was induced by a single oral dose of acetaminophen (2.5g/kg). Hemin was given as a single s.c. injection (40μmol/kg), 1h following acetaminophen administration. Hemin treatment restored blood urea nitrogen and serum creatinine levels that were elevated by acetaminophen. Hemin also compensated deficits in the antioxidant defense mechanisms (reduced glutathione, and catalase and superoxide dismutase activities), and suppressed lipid peroxidation in renal tissue resulted from acetaminophen administration. Hemin attenuated the acetaminophen-induced elevations in renal tumor necrosis factor-α and nitric oxide levels, and caspase-3 activity. Additionally, hemin ameliorated acetaminophen-induced renal damage observed by light microscopic examination. The therapeutic effect afforded by hemin was abolished by prior administration of zinc protoporphyrin-IX, the heme oxygenase-1 inhibitor. It was concluded that hemin represents a potential therapeutic option to protect renal tissue from the detrimental effects of acute acetaminophen overdose.

Proteinuria is unrelated to the extent of acute acetaminophen overdose: a prospective clinical study

BACKGROUND

Acute renal failure is a recognized complication of acute acetaminophen overdose. Its detection depends on rising creatinine concentrations, which is an insensitive method. The present study examined whether proteinuria might correspond with the extent of acute acetaminophen exposure as a possible early marker of renal effects.

METHODS

A prospective case-control study included patients attending the emergency department within 24 hours of acetaminophen ingestion. A urine specimen was collected within 12 hours of hospital attendance for creatinine, albumin, and protein determination. Equivalent 4-hour acetaminophen concentrations were used to indicate drug exposure: mild if >100 g/L (>662 mmol/L), moderate if 100-200 g/L (662-1323 mmol/L), or severe if <200 g/L (<1323 mmol/L). Data are presented as median (interquartile range) and groups compared using Mann Whitney and chi-square tests.

RESULTS

Seventy patients were studied (17 men, 53 women), age 37 years (23-45 years). The stated acetaminophen dose was 15 g (8-20 g), and interval between ingestion and presentation was 4.6 hours (4.1-7.9 hours). Urinary albumin concentrations were 8 mg/L (0-12 mg/L) in the mild group, 12 mg/L (5-25 mg/L) in the moderate group, and 11 mg/L (6-22 mg/L) in the severe group. Total protein concentrations were 90 mg/L (50-183 mg/L), 70 mg/L (40 to 130 mg/L), and 110 mg/L (75-205 mg/L), respectively. The proportions of patients who had urine albumin:creatinine ratio >3 mg/mmol were 20.8%, 23.5%, and 21.2%, respectively. None of the patients developed acute renal failure.

CONCLUSIONS

No relationship was found between the extent of acute acetaminophen exposure and proteinuria. Further work is required to examine whether urinary protein excretion is altered in patients who subsequently develop acute renal failure following acetaminophen overdose.

Acetaminophen-induced nephrotoxicity: pathophysiology, clinical manifestations, and management

Acetaminophen-induced liver necrosis has been studied extensively, but the extrahepatic manifestations of acetaminophen toxicity are currently not described well in the literature. Renal insufficiency occurs in approximately 1-2% of patients with acetaminophen overdose. The pathophysiology of renal toxicity in acetaminophen poisoning has been attributed to cytochrome P-450 mixed function oxidase isoenzymes present in the kidney, although other mechanisms have been elucidated, including the role of prostaglandin synthetase and N-deacetylase enzymes. Paradoxically, glutathione is considered an important element in the detoxification of acetaminophen and its metabolites; however, its conjugates have been implicated in the formation of nephrotoxic compounds. Acetaminophen-induced renal failure becomes evident after hepatotoxicity in most cases, but can be differentiated from the hepatorenal syndrome, which may complicate fulminant hepatic failure. The role of N-acetylcysteine therapy in the setting of acetaminophen-induced renal failure is unclear. This review will focus on the pathophysiology, clinical features, and management of renal insufficiency in the setting of acute acetaminophen toxicity.

CASE

A 47-year-old female was found lethargic at home and brought by ambulance to an emergency department. History from family members suggested an inadvertent acetaminophen overdose, and she had last been seen a few hours earlier. She reportedly ingested 18 tablets of 500 mg acetaminophen (APAP) over the previous two days because she had run out of her prescription pain medication. Her past medical history was significant for fibromyalgia, arthritis, and a prior gastric bypass procedure. She had no history of alcohol abuse or renal insufficiency. She was lethargic. Vital signs: BP 128/96 mmHg, pulse 112/min, respirations 32/min; pulse oximetry 98% on 2L nasal cannula oxygen. Laboratory studies: BUN 9 mg/dL, creatinine 0.9 mg/dl, acetaminophen 12 mcg/mL, AST 5409 u/L and ALT 1085 u/L. A urinalysis was negative for blood with trace protein and ketones. A urine drug screen was positive for marijuana and opioid metabolites. At the initial hospital, she was treated with N-acetylcysteine (NAC) orally. Subsequently, she developed fulminant hepatic failure with elevated transaminases, hypoglycemia, and coagulopathy (Tables 1A and 1B). She was transferred to our facility two days after initial presentation for liver transplant evaluation. At that time, her APAP level was 2.0 mg/L. Oral NAC therapy was continued after transfer. The patient's liver function subsequently improved and she ultimately did not require transplantation. She did develop acute renal failure during the course of her hospitalization, with a creatinine of 2.3 mg/dL on transfer, which increased to 8.1 mg/dL nine days later (approximately 11-13 days post-ingestion). Medical toxicology was consulted by the intensive care unit team to address whether this was acetaminophen-induced renal failure and if there was a role for NAC in this setting.

Effect of gamma irradiation on the efficacy of beta-glucan against acetaminophen induced toxicity in mice

The present study was conducted to compare the efficacy of unirradiated beta-glucan (UBG) and gamma irradiated beta-glucan (GIBG) against acetaminophen (APAP) induced hepatotoxicity in mice. Mice of BALB/c strain were pretreated with UBG and GIBG (50mg/kg, p.o.) for 7 days and on the 8th day they received an overdose of APAP (500 mg/kg, i.p.). Eight hours after the APAP injection, the levels of serum aminotransferase (AST) and alanine aminotransferase (ALT) were measured and liver, kidney and lung tissue were examined for morphological changes. A significant elevation (p<0.001) of the levels of AST and ALT was observed in mice toxicated with APAP. Histology data revealed severe liver centrilobular necrosis, portal vein damage with apparent toxicity in renal glomerulus and lung inflammation associated with edema. However, a significant inhibition (p<0.05) in the elevation of AST and ALT was observed in mice that received UBG and GIBG compared with APAP-treated mice. Histology examination revealed the non-statistical difference between the protective effects of GIBG and UBG against acetaminophen challenge. In conclusion, it was demonstrated that gamma irradiation induced no severe alteration in the protective activity of beta-glucan against APAP-induced hepatotoxicity.

Acetaminophen hepatotoxicity

Acetaminophen is a commonly used antipyretic and analgesic agent. It is safe when taken at therapeutic doses; however, overdose can lead to serious and even fatal hepatotoxicity. The initial metabolic and biochemical events leading to toxicity have been well described, but the precise mechanism of cell injury and death is unknown. Prompt recognition of overdose, aggressive management, and administration of N-acetylcysteine can minimize hepatotoxicity and prevent liver failure and death. Liver transplantation can be lifesaving for those who develop acute liver failure.

Propylthiouracil attenuates acetaminophen-induced renal damage in the rat

BACKGROUND

To date, there is no specific antidote to acetaminophen poisoning. Propylthiouracil (PTU) has been shown to be protective against acetaminophen (APAP)-induced liver damage in rats; however, the nephroprotective effect of propylthiouracil has not been studied yet.

METHODS

In order to verify this, rats were given different doses of PTU (100, 200 or 400 mg/kg per body weight, orally) 1 h before a nephrotoxic dose of APAP (1,000 mg/kg per body weight, intraperitoneally (i.p.)).

RESULTS

Propylthiouracil pretreatment significantly reduced APAP-induced nephrotoxicity in a dose-dependant manner, as evidenced by reduction in plasma creatinine and by amelioration of renal pathology (interstitial congestion, tubular cell degeneration and necrosis).

CONCLUSION

The mechanism of protection by PTU is probably not due to the sparing effect of non-protein thiol (approximately 95% of which is reduced glutathione), as similar depletion of renal glutathione was observed regardless of PTU pretreatment; other mechanisms are suggested.