Drug-Induced Liver Injury and Individual Cell Models

Drug-induced liver injury (DILI) is the most common cause of acute liver failure and accounts for the majority of regulatory actions on drugs. Furthermore, DILI is a relevant cause for project terminations in pharmaceutical development. The idiosyncratic form of DILI is especially a threat in late clinical development phases and postmarketing, respectively. Even the occurrence of only a few idiosyncratic DILI cases in late clinical development or postmarketing may suffice to terminate or withdraw an otherwise promising therapy. Despite advances in preclinical assessment of dose-dependent toxicity, idiosyncratic DILI is still a big challenge for in vitro research: it not only requires individualized models but also a huge number of tests. We have developed and investigated MetaHeps\circledR, a technology involving hepatocyte-like cells generated from peripheral monocytes without genetic modifications. These cells exhibit several hepatocyte-like characteristics and show donor-specific activities of drug-metabolizing enzymes. With MetaHeps we have performed in vitro investigations in patients with DILI suspicion. By investigating MetaHeps derived from DILI patients we could show increased in vitro susceptibility to the drugs involved in the individual patients. MetaHeps testing could also rule out DILI and help to identify other causes of acute liver injury. Moreover, MetaHeps identified the causative agent in polymedicated patients. In conclusion, in vitro research of idiosyncratic DILI requires individual cell models which produce results comparable to the clinical situation. We suggest the MetaHeps technology as a novel tool to cope with these challenges of DILI

Monocyte-derived hepatocyte-like cells for causality assessment of idiosyncratic drug-induced liver injury

Background Idiosyncratic drug-induced liver injury (iDILI) is a frequent cause of acute liver injury and a serious problem in late stage drug-development. Its diagnosis is one of the most challenging in hepatology, since it is done by exclusion and relies on expert opinion. Until now no reliable in vitro test exists to support the diagnosis of iDILI. In some instances it is impossible to determine the causative drug in polymedicated patients. Aim To investigate if monocyte-derived hepatocyte-like (MH) cells might be a tool supporting clinical judgment for iDILI diagnosis and causality assessment. Methods This prospective study included 54 patients with acute liver injury and intake of at least one drug. Thirty-one patients were diagnosed with iDILI based on causality likelihood. MH cells were generated from every patient and in vitro toxicity of the respective drugs was assessed by lactate-dehydrogenase release. The results from MH cells and RUCAM, the most widely used scoring system as methods to support clinical judgement were compared. Results MH cells showed enhanced toxicity in 29 of the 31 patients with iDILI, similar to RUCAM score. MH cells exhibited negative results in the 23 non-DILI cases, whereas RUCAM indicated possible iDILI in six cases. Analysis of the comedications also showed superior specificity of MH cells. No MH cell toxicity of the drugs showing toxicity in patients with iDILI was observed in MH cells of healthy donors. Conclusions In this pilot study in vitro testing using MH cells derived from patients with acute liver injury was able to identify patients with iDILI with an excellent sensitivity and a higher specificity than RUCAM, the most widely used current causality assessment score. Therefore, MH cells could be useful to identify the causative drugs even in polymedicated patients by adding objective data to causality assessment

Liver Injury Associated with Metamizole Exposure: Features of an Underestimated Adverse Event

INTRODUCTION AND OBJECTIVE The potential of metamizole to cause drug-induced liver injury (DILI) has received increasing attention. We investigated the distinguishing features of a case series comprising 32 patients with suspected metamizole-induced DILI. METHODS For the current analysis, 32 of 238 patients with DILI included in our prospective study on drugs potentially causing DILI were included. Diagnosis of DILI was based on expert opinion and RUCAM (Roussel Uclaf Causality Assessment Method) score and supported by an in vitro test using monocyte-derived hepatocyte-like cells. RESULTS Suspected metamizole-DILI was characterised by a female predominance, hepatocellular pattern of injury, high proportion of antinuclear antibody positivity, and predominance of eosinophilic cell infiltration and necrosis in the histopathological analysis. With 22%, a high proportion of these metamizole-associated liver injury cases developed acute liver failure, which was characterised by a longer latency of metamizole use and more pronounced liver biochemistry abnormalities at onset and peak levels. Furthermore, jaundice was a common finding in the metamizole-associated liver injury cases with 66% presenting with peak bilirubin levels of 3~mg/dL or higher, which was associated with a worse outcome and a higher frequency of acute liver failure. CONCLUSIONS Our analysis of a well-characterised DILI cohort further supports the potential of metamizole causing DILI and provides important features for the establishment of a signature pattern of liver injury observed in patients treated with metamizole. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov: NCT02353455

Feasibility of the MELD score as a screening tool for pharmacists to identify patients with impaired hepatic function at hospital admission

WHAT IS KNOWN AND OBJECTIVE Hepatic impairment (HI) is a known risk factor for drug safety. The MELD score (Model-for-endstage-liver-disease), calculated from serum creatinine, bilirubin and International Normalized Ratio (INR), is a promising screening tool corresponding to Child-Pugh Score (CPS) for drug adjustment. We tested the feasibility of MELD as an automatic screening tool accounting for correct calculation, interfering factors (IF) and detection of patients corresponding to CPS-B/C potentially requiring drug adjustment. METHODS We retrospectively calculated MELD for a 3-month cohort of surgical patients and assessed need for adjustment of MELD parameters to standard values. IF for INR (oral anticoagulants) and serum creatinine (renal insufficiency (RI; eGFR\textless60~ml/min/1.73m²); as well as drugs elevating creatinine levels (DECL)) and the number of patients with MELD scores corresponding to CPS-B/C were analysed. For MELD \geq7.5, liver and bile diagnoses were recorded. RESULTS AND DISCUSSION Of 1183 patients, MELD was calculable for 761 (64%; median 7.5, range 6.4-36.8). Parameters had to be adjusted for 690 (91%) patients. IF of parameters were RI in 172 (23%), INR-elevating drugs in 105 (14%) and DECL in 33 (4%) patients. Of 335 (44%) patients with MELD \geq7.5, 122 (36%) had documented liver or bile diagnoses. MELD 10-\textless15 (corresponding to CPS-B) was found for 105 (14%), MELD \geq15 (corresponding to CPS-C) for 66 (9%) of the 761 patients with a calculated MELD. Referred to all patients, drug adjustments due to possible HI were recommendable for 14% of patients with suspected CPS-B/C. WHAT IS NEW AND CONCLUSION MELD is a feasible screening tool for HI as a risk factor for drug safety at hospital admission when appropriately considering correct parameter adjustment and RI and INR-elevating drugs as IF. Further evaluation of sensitivity and specificity is needed

Hepatic Impairment as a Risk Factor for Drug Safety: Suitability and Comparison of Four Liver Scores as Screening Tools

Hepatic impairment (HI) influences the pharmacokinetics and pharmacodynamics of drugs and represents an important risk factor for drug safety. A reliable screening tool for HI identification at hospital admission by pharmacists would be desirable but is currently lacking. Therefore, we tested four liver scores as potential screening instruments. We retrospectively recorded liver/bile diagnoses, symptoms and abnormalities (summarized as hepatic findings) of 200 surgical patients followed by an assessment of the relevance of these findings for drug therapy (rating). The agreement between the Model of Endstage Liver Disease (MELD), Non-alcoholic fatty liver disease fibrosis score (NFS), Fibrosis 4 index (FIB-4), and aspartate-aminotransferase to platelet ratio index (APRI) and the rating was quantified by Cohen’s Kappa. The performance of the scores in this setting was further evaluated by their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Of 200 patients, 18 (9%) had hepatic findings relevant for drug therapy. Fair agreement was found for FIB-4 and MELD and slight agreement for APRI and NFS compared to the rating. The highest values for sensitivity, specificity, PPV, and NPV were 41.2% (MELD), 99.3% (APRI), 66.7% (APRI), and 93.6% (MELD), respectively. Due to low performance, none of the scores can be recommended for clinical use as a single screening tool for HI at hospital admission

Proteomics Analysis of Monocyte-Derived Hepatocyte-Like Cells Identifies Integrin Beta 3 as a Specific Biomarker for Drug-Induced Liver Injury by Diclofenac

Idiosyncratic drug-induced liver injury (iDILI) is a major cause of acute liver failure resulting in liver transplantation or death. Prediction and diagnosis of iDILI remain a great challenge, as current models provide unsatisfying results in terms of sensitivity, specificity, and prognostic value. The absence of appropriate tools for iDILI detection also impairs the development of reliable biomarkers. Here, we report on a new method for identification of drug-specific biomarkers. We combined the advantages of monocyte-derived hepatocyte-like (MH) cells, able to mimic individual characteristics, with those of a novel mass spectrometry-based proteomics technology to assess potential biomarkers for Diclofenac-induced DILI. We found over 2,700 proteins differentially regulated in MH cells derived from individual patients. Herefrom, we identified integrin beta 3 (ITGB3) to be specifically upregulated in Diclofenac-treated MH cells from Diclofenac-DILI patients compared to control groups. Finally, we validated ITGB3 by flow cytometry analysis of whole blood and histological staining of liver biopsies derived from patients diagnosed with Diclofenac-DILI. In summary, our results show that biomarker candidates can be identified by proteomics analysis of MH cells. Application of this method to a broader range of drugs in the future will exploit its full potential for the development of drug-specific biomarkers. Data are available via ProteomeXchange with identifier PXD008918

Early ALT response to corticosteroid treatment distinguishes idiosyncratic drug‐induced liver injury from autoimmune hepatitis

Background Drug‐induced liver injury (DILI) and idiopathic autoimmune hepatitis (AIH) are competing diagnoses in patients with acute liver injury (ALI) and drug intake. In absence of unequivocal markers, scores like RUCAM and AIH are used to distinguish both entities. However, in some cases the diagnosis remains ambiguous. Our aim was to identify a simple parameter to discriminate DILI and AIH shortly after starting corticosteroid treatment. Methods For the current analysis, 44 patients with ALI who took at least one drug and who received corticosteroids were included and comprised 22 DILI and 22 AIH cases. Scores of AIH and RUCAM were calculated at initial presentation, the final diagnosis was made from analysing the course of disease. Changes in the serum alanine aminotransferase (ALT) concentrations after starting corticosteroid treatment were determined and compared between the DILI and AIH groups. Results Fifty‐nine per cent of patients (n = 26) were correctly classified at presentation by AIH score and RUCAM respectively. However, in one‐third (n = 13) of the 44 patients, results were inconclusive and five other patients were misclassified. The decrease in ALT levels 1 week after the initiation of steroid therapy was significantly more pronounced in patients with the final diagnosis of DILI than in AIH patients (accuracy 77%). This difference was also observed in the 18 initially misclassified or inconclusive cases (accuracy 83%). Conclusion Short‐term response of ALT to corticosteroid therapy helps to differentiate DILI and AIH. This finding may be helpful in treatment decision for patients with inconclusive diagnostic scores

Proteomics Analysis of Monocyte-Derived Hepatocyte-Like Cells Identifies Integrin Beta 3 as a Specific Biomarker for Drug-Induced Liver Injury by Diclofenac

Idiosyncratic drug-induced liver injury (iDILI) is a major cause of acute liver failure resulting in liver transplantation or death. Prediction and diagnosis of iDILI remain a great challenge, as current models provide unsatisfying results in terms of sensitivity, specificity, and prognostic value. The absence of appropriate tools for iDILI detection also impairs the development of reliable biomarkers. Here, we report on a new method for identification of drug-specific biomarkers. We combined the advantages of monocyte-derived hepatocyte-like (MH) cells, able to mimic individual characteristics, with those of a novel mass spectrometry-based proteomics technology to assess potential biomarkers for Diclofenac-induced DILI. We found over 2,700 proteins differentially regulated in MH cells derived from individual patients. Herefrom, we identified integrin beta 3 (ITGB3) to be specifically upregulated in Diclofenac-treated MH cells from Diclofenac-DILI patients compared to control groups. Finally, we validated ITGB3 by flow cytometry analysis of whole blood and histological staining of liver biopsies derived from patients diagnosed with Diclofenac-DILI. In summary, our results show that biomarker candidates can be identified by proteomics analysis of MH cells. Application of this method to a broader range of drugs in the future will exploit its full potential for the development of drug-specific biomarkers. Data are available via ProteomeXchange with identifier PXD008918

Effect of nanomolar Concentrations of the Mycotoxin Ochratoxin A on Calciumhoneostasis, Proliferation and hormonal Signaltransduction in human proximal tubular cells

Hintergrund: Der weitverbreitete und karzinogene Pilzmetabolit Ochratoxin A (OTA) beeinflußt die Funktion und das Wachstumsverhalten renaler Zellen. In höheren Konzentrationen reduziert OTA auch die Integrität der Zellen. Untersucht wurde die mögliche Beteiligung von Änderungen der zellulären Calciumhomöostase an den Wirkungen von OTA in nanomolaren Konzentrationen. Methoden: Immortalisierte menschliche Nierenepithelzellen (IHKE) wurden verwendet, um die Effekte von OTA auf die zytosolische Calciumhomöostase ([Ca2+]i), Zellwachstum und und -integrität zu untersuchen. 1 nmol/l OTA potenzierte Ca2+-abhängig die EGF- und Ang II-induzierte Zellproliferation. Ca2+-unahängige Zelluntergänge und Reduktion der Zellzahl konnte nur nach 24-stündiger Inkubation mit einer Schwellenkonzentration von >10 nmol/l beobachtet werden. Innerhalb von Sekunden wurden durch OTA reversible und konzentrationsabhänige [Ca2+]i-Oszillationen mit einer Schwellenkonzentration von 0.1 nmol/l hervorgerufen. Die Oszillationen wurden durch Reduktion des extrazellulären Ca2+, den Ca2+-Kanalblocker SK&F 96365 und durch Hemmung der der Phospholipase C verhindert. Der durch OTA hervorgerufene Ca2+-Einstrom war auch nach Entleerung von Ca2+-Speichern durch Schwellenkonzentration das ebenfalls die Oszollationen hemmte, noch vorhanden. Zusätzlich steigerte OTA den Füllungszustand von Thapsigargin-empfindlichen Ca2+-Speichern und stimulierte die Aktivität der Thapsigargin-empfindlichen Ca2+-ATPase. Eine 10-minütige Inkubation mit OTA erhöhte den zellulären cAMP-Gehalt dosisabhängig. Der Proteinkinase A Inhibitor H-89 unterdrückte die OTA-induzierten Ca2+- Oszillationen. 1 nM OTA potenzierte die Effekte von Angiotensin II und EGF auf [Ca2+]i. Schlußfolgerungen: (i) OTA beeinträchtigt in niedrig-nanomolaren Konzentrationen, die im Rahmen der natürlichen Exposition auftreten können, reversibel die Ca2+-Homöostase in menschlichen proximalen Tubuluszellen. (ii) OTA verursacht dosis-abhängige [Ca2+]i-Oszillationen die auf OTA-induzierten Ca2+-Einstrom und Thapsigargin-sensitive Ca2+-Speicher angewiesen sind. (iii) Ferner interagieren niedrig-nanomoler Konzentrationen von OTA mit hormonellen Ca2+-Signalen, was z.B. zu einem veränderten zellulären Proliferationsverhalten führt. (iv) Die Verminderung der Zellintegrität durch höhere OTA-Konzentrationen hängt nicht von Veränderungen der Ca2+-Homöostase ab. (v) Die durch OTA hervogerufene renale Dysfunktion scheint, zumindest teilweise, auf Wechselwirkungen mit zellulären Signaltransduktionsmechanismen zu beruhen und nicht auf Zellzerstörung.The ubiquitous nephrotoxic and carcinogenic fungal metabolite ochratoxin A (OTA) interacts with renal cell function and growth. At higher concentrations OTA also reduces cell integrity. The possible contribution of changes in cellular Ca2+-homeostasis to the effects of OTA at nanomolar concentrations was investigated. Immortalized human kidney epithelial (IHKE) cells were used to investigate the effects of OTA on cytosolic calcium homeostasis ([Ca2+]i), cell growth and cell viability. 1 nmol/l OTA potentiated EGF- and Ang II-induced cell proliferation in a Ca2+-dependent manner. A Ca2+-independent decrease in cell viability and cell number could be observed only after 24 h-exposure with threshold concentrations > 10 nmol/l. Within seconds OTA evoked reversible and concentration-dependent [Ca2+]i oscillations with a threshold concentration of 0.1 nM. The oscillations were abolished by removal of extracellular Ca2+, by the Ca2+-channel blocker SK&F 96365 and by inhibition of phospholipase C. OTA-induced activation of Ca2+-influx was still present after store depletion with thapsigargin, which blunted the oscillations. In addition, OTA increased the filling state of thapsigargin-sensitive Ca2+-stores and stimulated the thapsigargin-sensitive Ca2+-ATPase activity. 10 min incubation with OTA increased cellular cAMP content in a dose-dependent manner. The protein kinase A inhibitor H-89 suppressed OTA-induced Ca2+-oscillations. 1 nM OTA potentiated the effects of angiotensin II and EGF on [Ca2+]i. Conclusions: (i) OTA impairs Ca2+-homeostasis in human renal epithelial cells in a reversible manner at low nanomolar concentrations, which occur during dietary exposure. (ii) OTA causes dose-dependent [Ca2+]i oscillations which are dependent on OTA-induced Ca2+-influx and thapsigargin-sensitive Ca2+-stores. (iii) Furthermore, low nanomolar OTA interferes with hormonal Ca2+ signaling leading, for example, to altered cell proliferation. (iv) Reduction of cell integrity at higher concentrations does not depend on changes of Ca2+-homeostasis. (v) OTA-induced renal dysfunction at low nanomolar concentrations seems to result, at least in part, from the interaction with cellular signaling mechanisms and not from cell destruction