Darren G. Craig

Circulating microRNAs as potential markers of human drug‐induced liver injury

New biomarkers of liver injury are required in the clinic and in preclinical pharmaceutical evaluation. Previous studies demonstrate that two liver‐enriched microRNAs (miR‐122 and miR‐192) are promising biomarkers of acetaminophen‐induced acute liver injury (APAP‐ALI) in mice. We have examined these molecules, for the first time, in humans with APAP poisoning. Serum miR‐122 and miR‐192 were substantially higher in APAP‐ALI patients, compared to healthy controls (median ΔΔCt [25th, 75th percentile]) (miR‐122: 1,265 [491, 4,270] versus 12.1 [7.0, 26.9], P < 0.0001; miR‐192: 6.9 [2.0, 29.2] versus 0.44 [0.30, 0.69], P < 0.0001). A heart‐enriched miR‐1 showed no difference between APAP‐ALI patients and controls, whereas miR‐218 (brain‐enriched) was slightly higher in the APAP‐ALI cohort (0.17 [0.07, 0.50] versus 0.07 [0.04, 0.12]; P = 0.01). In chronic kidney disease (CKD) patients, miR‐122 and ‐192 were modestly higher, compared to controls (miR‐122: 32.0 [21.1, 40.9] versus 12.1 [7.0, 26.9], P = 0.006; miR‐192: 1.2 [0.74, 1.9] versus 0.44 [0.30, 0.69], P = 0.005), but miR‐122 and ‐192 were substantially higher in APAP‐ALI patients than CKD patients (miR‐122: P < 0.0001; miR‐192: P < 0.0004). miR‐122 correlated with peak ALT levels in the APAP‐ALI cohort (Pearson R = 0.46, P = 0.0005), but not with prothrombin time. miR‐122 was also raised alongside peak ALT levels in a group of patients with non‐APAP ALI. Day 1 serum miR‐122 levels were almost 2‐fold higher in APAP‐ALI patients who satisfied Kings College Criteria (KCC), compared to those who did not satisfy KCC, although this did not reach statistical significance (P = 0.15). Conclusion: This work provides the first evidence for the potential use of miRNAs as biomarkers of human drug‐induced liver injury. (HEPATOLOGY 2011;)

Molecular forms of HMGB1 and keratin-18 as mechanistic biomarkers for mode of cell death and prognosis during clinical acetaminophen hepatotoxicity

BACKGROUND & AIMS Full length keratin-18 (FL-K18) and High Mobility Group Box-1 (HMGB1) represent circulating indicators of necrosis during acetaminophen (APAP) hepatotoxicity in vivo. In addition, the caspase-cleaved fragment of K18 (cK18) and hyper-acetylated HMGB1 represent serum indicators of apoptosis and immune cell activation, respectively. The study aim was to assess their mechanistic utility to establish the balance between apoptosis, necrosis, and immune cell activation throughout the time course of clinical APAP hepatotoxicity. METHODS HMGB1 (total, acetylated) and K18 (apoptotic, necrotic) were identified and quantified by novel LC-MS/MS assays in APAP overdose patients (n=78). RESULTS HMGB1 (total; 15.4±1.9ng/ml, p<0.01, acetylated; 5.4±2.6ng/ml, p<0.001), cK18 (5649.8±721.0U/L, p<0.01), and FL-K18 (54770.2±6717.0U/L, p<0.005) were elevated in the sera of APAP overdose patients with liver injury compared to overdose patients without liver injury and healthy volunteers. HMGB1 and FL-K18 correlated with alanine aminotransferase (ALT) activity (R(2)=0.60 and 0.58, respectively, p<0.0001) and prothrombin time (R(2)=0.62 and 0.71, respectively, p<0.0001). Increased total and acetylated HMGB1 and FL-K18 were associated with worse prognosis (Kings College Criteria) or patients that died/required liver transplant compared to spontaneous survivors (all p<0.05-0.001), a finding not reflected by ALT and supported by ROC analysis. Acetylated HMGB1 was a better predictor of outcome than the other markers of cell death. CONCLUSIONS K18 and HMGB1 represent blood-based tools to investigate the cell death balance clinical APAP hepatotoxicity. Activation of the immune response was seen later in the time course as shown by the distinct profile of acetylated HMGB1 and was associated with worse outcome.

Staggered overdose pattern and delay to hospital presentation are associated with adverse outcomes following paracetamol-induced hepatotoxicity

AIMS Paracetamol (acetaminophen) poisoning remains the major cause of severe acute hepatotoxicity in the UK. In this large single centre cohort study we examined the clinical impact of staggered overdoses and delayed presentation following paracetamol overdose. RESULTS Between 1992 and 2008, 663 patients were admitted with paracetamol-induced severe liver injury, of whom 161 (24.3%) had taken a staggered overdose. Staggered overdose patients were significantly older and more likely to abuse alcohol than single time point overdose patients. Relief of pain (58.2%) was the commonest rationale for repeated supratherapeutic ingestion. Despite lower total ingested paracetamol doses and lower admission serum alanine aminotransferase concentrations, staggered overdose patients were more likely to be encephalopathic on admission, require renal replacement therapy or mechanical ventilation and had higher mortality rates compared with single time point overdoses (37.3% vs. 27.8%, P= 0.025), although this overdose pattern did not independently predict death. The Kings College poor prognostic criteria had reduced sensitivity (77.6, 95% CI 70.8, 81.5) for this pattern of overdose. Of the 396/450 (88.0%) single time point overdoses in whom accurate timings could be obtained, 178 (44.9%) presented to medical services >24 h following overdose. Delayed presentation beyond 24 h post overdose was independently associated with death/liver transplantation (OR 2.25, 95% CI 1.23, 4.12, P= 0.009). CONCLUSIONS Both delayed presentation and staggered overdose pattern are associated with adverse outcomes following paracetamol overdose. These patients are at increased risk of developing multi-organ failure and should be considered for early transfer to specialist liver centres.

Review article: the current management of acute liver failure

Aliment Pharmacol Ther 31, 345–358

Circulating apoptotic and necrotic cell death markers in patients with acute liver injury.

Background: The host response to cell death underpins the immune activation that follows acute liver injury, and measurement of circulating cell death markers could therefore aid prognostication following paracetamol overdose. Nucleosomes, formed during apoptosis, can complex with high‐mobility group box 1 (HMGB1) protein and may play a pathogenic role in liver injury.

Systematic review: prognostic tests of paracetamol-induced acute liver failure.

Aliment Pharmacol Ther 31, 1064–1076

Overdose pattern and outcome in paracetamol-induced acute severe hepatotoxicity

AIMS Paracetamol (acetaminophen) hepatotoxicity is the commonest cause of acute liver failure (ALF) in the UK. Conflicting data regarding the outcomes of paracetamol-induced ALF resulting from different overdose patterns are reported. METHODS Using prospectively defined criteria, we have analysed the impact of overdose pattern upon outcome in a cohort of 938 acute severe liver injury patients admitted to the Scottish Liver Transplantation Unit. RESULTS Between 1992 and 2008, 663 patients were admitted with paracetamol-induced acute severe liver injury. Of these patients, 500 (75.4%) had taken an intentional paracetamol overdose, whilst 110 (16.6%) had taken an unintentional overdose. No clear overdose pattern could be determined in 53 (8.0%). Unintentional overdose patients were significantly older, more likely to abuse alcohol, and more commonly overdosed on compound narcotic/paracetamol analgesics compared with intentional overdose patients. Unintentional overdoses had significantly lower admission paracetamol and alanine aminotransferase concentrations compared with intentional overdoses. However, unintentional overdoses had greater organ dysfunction at admission, and subsequently higher mortality (unintentional 42/110 (38.2%), intentional 128/500 (25.6%), P < 0.001). The Kings College poor prognostic criteria had reduced sensitivity in unintentional overdoses (77.8%, 95% confidence intervals (CI) 62.9, 88.8) compared with intentional overdoses (89.9%, 95% CI 83.4, 94.5). Unintentional overdose was independently predictive of death or liver transplantation on multivariate analysis (odds ratio 1.91 (95% CI 1.07, 3.43), P = 0.032). CONCLUSIONS Unintentional paracetamol overdose is associated with increased mortality compared with intentional paracetamol overdose, despite lower admission paracetamol concentrations. Alternative prognostic criteria may be required for unintentional paracetamol overdoses.

Comprehensive microRNA profiling in acetaminophen toxicity identifies novel circulating biomarkers for human liver and kidney injury.

Our objective was to identify microRNA (miRNA) biomarkers of drug-induced liver and kidney injury by profiling the circulating miRNome in patients with acetaminophen overdose. Plasma miRNAs were quantified in age- and sex-matched overdose patients with (N = 27) and without (N = 27) organ injury (APAP-TOX and APAP-no TOX, respectively). Classifier miRNAs were tested in a separate cohort (N = 81). miRNA specificity was determined in non-acetaminophen liver injury and murine models. Sensitivity was tested by stratification of patients at hospital presentation (N = 67). From 1809 miRNAs, 75 were 3-fold or more increased and 46 were 3-fold or more decreased with APAP-TOX. A 16 miRNA classifier model accurately diagnosed APAP-TOX in the test cohort. In humans, the miRNAs with the largest increase (miR-122-5p, miR-885-5p, miR-151a-3p) and the highest rank in the classifier model (miR-382-5p) accurately reported non-acetaminophen liver injury and were unaffected by kidney injury. miR-122-5p was more sensitive than ALT for reporting liver injury at hospital presentation, especially combined with miR-483-3p. A miRNA panel was associated with human kidney dysfunction. In mice, miR-122-5p, miR-151a-3p and miR-382-5p specifically reported APAP toxicity - being unaffected by drug-induced kidney injury. Profiling of acetaminophen toxicity identified multiple miRNAs that report acute liver injury and potential biomarkers of drug-induced kidney injury.

Diagnosis of Febrile Illnesses other than Ebola Virus Disease at an Ebola Treatment Unit in Sierra Leone

Abstract Patients with febrile illnesses presenting to an Ebola treatment unit in Sierra Leone had a wide range of diagnoses other than Ebola virus disease. Rapid diagnostic tests were useful in confirming these diagnoses, reducing the length of patient stay with valuable consequences. These alternative diagnoses should assist in future planning.

The systemic inflammatory response syndrome and sequential organ failure assessment scores are effective triage markers following paracetamol (acetaminophen) overdose

Aliment Pharmacol Ther 2011; 34: 219–228