| 1. |
- Oorts, Marlies, et al.
(författare)
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Bosentan Alters Endo- and Exogenous Bile Salt Disposition in Sandwich-Cultured Human Hepatocytes
- 2021
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 379:1, s. 20-32
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Tidskriftsartikel (refereegranskat)abstract
- Bosentan, a well-known cholestatic agent, was not identified as cholestatic at concentrations up to 200 mM based on the drug-induced cholestasis (DIC) index value, determined in a sandwich-cultured human hepatocyte (SCHH)-based DIC assay. To obtain further quantitative insights into the effects of bosentan on cellular bile salt handling by human hepatocytes, the present study determined the effect of 2.5-25 mu M bosentan on endogenous bile salt levels and on the disposition of 10 mu M chenodeoxycholic acid (CDCA) added to the medium in SCHHs. Bosentan reduced intracellular as well as extracellular concentrations of both endogenous glycochenodeoxycholic acid (GCDCA) and glycocholic acid in a concentration-dependent manner. When exposed to 10 mu M CDCA, bosentan caused a shift from canalicular efflux to sinusoidal efflux of GCDCA. CDCA levels were not affected. Our mechanistic model confirmed the inhibitory effect of bosentan on canalicular GCDCA clearance. Moreover, our results in SCHHs also indicated reduced GCDCA formation. We confirmed the direct inhibitory effect of bosentan on CDCA conjugation with glycine in incubations with liver S9 fraction.SIGNIFICANCE STATEMENT Bosentan was evaluated at therapeutically relevant concentrations (2.5-25 mu M) in sandwich-cultured human hepatocytes. It altered bile salt disposition and inhibited canalicular secretion of glycochenodeoxycholic acid (GCDCA). Within 24 hours, bosentan caused a shift from canalicular to sinusoidal efflux of GCDCA. These results also indicated reduced GCDCA formation. This study confirmed a direct effect of bosentan on chenodeoxycholic acid conjugation with glycine in liver S9 fraction.
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| 2. |
- Smits, Anne, et al.
(författare)
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Current knowledge, challenges and innovations in developmental pharmacology: A combined conect4children Expert Group and European Society for Developmental, Perinatal and Paediatric Pharmacology White Paper.
- 2021
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Ingår i: British journal of clinical pharmacology. - : Wiley. - 1365-2125 .- 0306-5251. ; 88:12, s. 4965-84
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Tidskriftsartikel (refereegranskat)abstract
- Developmental pharmacology describes the impact of maturation on drug disposition (pharmacokinetics, PK) and drug effects (pharmacodynamics, PD) throughout the paediatric age range. This paper, written by a multidisciplinary group of experts, summarizes current knowledge, and provides suggestions to pharmaceutical companies, regulatory agencies and academicians on how to incorporate the latest knowledge regarding developmental pharmacology and innovative techniques into neonatal and paediatric drug development. Biological aspects of drug absorption, distribution, metabolism and excretion throughout development are summarized. Although this area made enormous progress during the last two decades, remaining knowledge gaps were identified. Minimal risk and burden designs allow for optimally informative but minimally invasive PK sampling, while concomitant profiling of drug metabolites may provide additional insight in the unique PK behaviour in children. Furthermore, developmental PD needs to be considered during drug development, which is illustrated by disease- and/or target organ-specific examples. Identifying and testing PD targets and effects in special populations, and application of age- and/or population-specific assessment tools are discussed. Drug development plans also need to incorporate innovative techniques such as preclinical models to study therapeutic strategies, and shift from sequential enrolment of subgroups, to more rational designs. To stimulate appropriate research plans, illustrations of specific PK/PD-related as well as drug safety-related challenges during drug development are provided. The suggestions made in this joint paper of the Innovative Medicines Initiative conect4children Expert group on Developmental Pharmacology and the European Society for Developmental, Perinatal and Paediatric Pharmacology, should facilitate all those involved in drug development.
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| 3. |
- De Winter, Sabrina, et al.
(författare)
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Quantification and Explanation of the Variability of First-Dose Amikacin Concentrations in Critically Ill Patients Admitted to the Emergency Department : A Population Pharmacokinetic Analysis
- 2021
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Ingår i: European journal of drug metabolism and pharmacokinetics. - : Springer Nature. - 0378-7966 .- 2107-0180. ; 46, s. 653-663
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Tidskriftsartikel (refereegranskat)abstract
- Background: There may be a difference between the determinants of amikacin exposure in emergency department (ED) versus intensive care (ICU) patients, and the peak amikacin concentration varies widely between patients. Moreover, when the first dose of antimicrobials is administered to septic patients admitted to the ED, fluid resuscitation and vasopressors have just been initiated. Nevertheless, population pharmacokinetic modelling data for amikacin in ED patients are unavailable.Objective: The aim of this study was to quantify the interindividual variability (IIV) in the pharmacokinetics of amikacin in patients admitted to the ED and to identify the patient characteristics that explain this IIV.Methods: Patients presenting at the ED with severe sepsis or septic shock were randomly assigned to receive amikacin 25 mg/kg or 15 mg/kg intravenously. Blood samples were collected at 1, 6 and 24 h after the onset of the first amikacin infusion. Data were analysed using nonlinear mixed-effects modelling.Results: A two-compartment population pharmacokinetic model was developed based on 279 amikacin concentrations from 97 patients. The IIV in clearance (CL) and central distribution volume (V-1) were 71% and 26%, respectively. Body mass index (BMI), serum total protein level, serum sodium level, and fluid balance 24 h after amikacin administration explained 30% of the IIV in V-1, leaving 18% of the IIV unexplained. BMI and creatinine clearance according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation 24 h after amikacin administration explained 46% of the IIV in CL, and 39% remained unexplained.Conclusion: The IIV of amikacin pharmacokinetics in ED patients is large. Higher doses may be considered in patients with low serum sodium levels, low total protein levels, or a high fluid balance.
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| 4. |
- Dreesen, Erwin, et al.
(författare)
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Ceftriaxone dosing based on the predicted probability of augmented renal clearance in critically ill patients with pneumonia
- 2022
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press. - 0305-7453 .- 1460-2091. ; 77:9, s. 2479-2488
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: PTA of protein-unbound ceftriaxone may be compromised in critically ill patients with community-acquired pneumonia (CAP) with augmented renal clearance (ARC). We aimed to determine an optimized ceftriaxone dosage regimen based on the probability of developing ARC on the next day (P-ARC,P-d+1; www.arcpredictor.com). Patients and methods: Thirty-three patients enrolled in a prospective cohort study were admitted to the ICU with severe CAP and treated with ceftriaxone 2 g once daily. Patients contributed 259 total ceftriaxone concentrations, collected during 1 or 2 days (+/- 7 samples/day). Unbound fractions of ceftriaxone were determined in all peak and trough samples (n= 76). Population pharmacokinetic modelling and simulation were performed using NONMEM7.4. Target attainment was defined as an unbound ceftriaxone concentration >4 mg/L throughout the dosing interval. Results: A two-compartment population pharmacokinetic model described the data well. The maximal protein-bound ceftriaxone concentration decreased with lower serum albumin. Ceftriaxone clearance increased with body weight and P-ARC,P-d+1 determined on the previous day. A high P-ARC,P-d+1 was identified as a clinically relevant predictor for underexposure on the next day (area under the receiver operating characteristics curve 0.77). Body weight had a weak predictive value and was therefore considered clinically irrelevant. Serum albumin had no predictive value. An optimal P-ARC,P-d+1 threshold of 5.7% was identified (sensitivity 73%, specificity 69%). Stratified once- or twice-daily 2 g dosing when below or above the 5.7% P-ARC,P-d+1 cut-off, respectively, was predicted to result in 81% PTA compared with 47% PTA under population-level once-daily 2 g dosing. Conclusions: Critically ill patients with CAP with a high P-ARC,P-d+1 may benefit from twice-daily 2 g ceftriaxone dosing for achieving adequate exposure on the next day.
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| 5. |
- Elkayal, Omar, et al.
(författare)
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A Population Pharmacokinetic Modeling and Simulation Study of Posaconazole Oral Suspension in Immunocompromised Pediatric Patients : A Short Communication
- 2021
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Ingår i: Therapeutic Drug Monitoring. - : Wolters Kluwer. - 0163-4356 .- 1536-3694. ; 43:4, s. 512-518
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Tidskriftsartikel (refereegranskat)abstract
- Background: Posaconazole oral suspension emerged as a promising candidate for prophylaxis of invasive fungal infections in immunocompromised children. Its pharmacodynamic advantages include a broad-spectrum activity and a favorable safety profile; however, they are overshadowed by its large pharmacokinetic (PK) variability, which might cause subtherapeutic exposure. The aim of this study was to develop a population (pop) PK model based on rich sampling data to better understand the PK of posaconazole oral suspension in pediatric patients. Methods: Data were obtained from a prospective interventional study involving hospitalized pediatric patients with a hematologic malignancy and prophylactically treated with posaconazole oral suspension. After constructing the popPK model, the probability of target attainment (PTA; 100% T >= 0.7 mg/L) for prophylaxis under fixed, body weight-based, and body surface area-based dosing was evaluated using Monte Carlo simulation. Results: Fourteen patients contributed 112 posaconazole plasma concentrations. The PK of posaconazole was adequately described by a 1-compartment model with lag time 2.71 hours [13%]; nonlinear bioavailability ED50 99.1 mg/m(2) (fixed); first-order absorption rate constant 0.325 hour(-1) [27%]; apparent volume of distribution 1150 L [34%]; and apparent clearance 15.4 L/h [24%] (similar to 70-kg individual). The bioavailability decreased in the presence of diarrhea and co-treatment with a proton pump inhibitor (PPI). The unexplained interindividual variability in posaconazole PK remained large. The PTA was <85%, irrespective of the simulated dosing strategy. Patients without diarrhea and not administered a PPI had the highest PTA (85% under the fixed 300-mg dosing 4 times per day). Conclusions: Therapeutic drug monitoring is recommended during prophylactic posaconazole therapy in immunocompromised pediatric patients. Large-scale comparative studies are needed to characterize the PK variability between different posaconazole formulations in this cohort.
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| 6. |
- Gijsen, Matthias, et al.
(författare)
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Pharmacokinetic/Pharmacodynamic Target Attainment Based on Measured versus Predicted Unbound Ceftriaxone Concentrations in Critically Ill Patients with Pneumonia : An Observational Cohort Study
- 2021
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Ingår i: Antibiotics. - : MDPI. - 0066-4774 .- 2079-6382. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- The impact of ceftriaxone pharmacokinetic alterations on protein binding and PK/PD target attainment still remains unclear. We evaluated pharmacokinetic/pharmacodynamic (PK/PD) target attainment of unbound ceftriaxone in critically ill patients with severe community-acquired pneumonia (CAP). Besides, we evaluated the accuracy of predicted vs. measured unbound ceftriaxone concentrations, and its impact on PK/PD target attainment. A prospective observational cohort study was carried out in adult patients admitted to the intensive care unit with severe CAP. Ceftriaxone 2 g q24h intermittent infusion was administered to all patients. Successful PK/PD target attainment was defined as unbound trough concentrations above 1 or 4 mg/L throughout the whole dosing interval. Acceptable overall PK/PD target attainment was defined as successful target attainment in >= 90% of all dosing intervals. Measured unbound ceftriaxone concentrations (CEFu) were compared to unbound concentrations predicted from various protein binding models. Thirty-one patients were included. The 1 mg/L and 4 mg/L targets were reached in 26/32 (81%) and 15/32 (47%) trough samples, respectively. Increased renal function was associated with the failure to attain both PK/PD targets. Unbound ceftriaxone concentrations predicted by the protein binding model developed in the present study showed acceptable bias and precision and had no major impact on PK/PD target attainment. We showed suboptimal (i.e., <90%) unbound ceftriaxone PK/PD target attainment when using a standard 2 g q24h dosing regimen in critically ill patients with severe CAP. Renal function was the major driver for the failure to attain the predefined targets, in accordance with results found in general and septic ICU patients. Interestingly, CEFu was reliably predicted from CEFt without major impact on clinical decisions regarding PK/PD target attainment. This suggests that, when carefully selecting a protein binding model, CEFu does not need to be measured. As a result, the turn-around time and cost for ceftriaxone quantification can be substantially reduced.
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| 7. |
- Handin, Niklas
(författare)
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Proteomics informed investigation of human hepatocytes and liver tissue
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A successful drug needs to display beneficial absorption, distribution, metabolism, excretion and toxicity (ADME-Tox) profile. It is therefore important to investigate these properties during the drug discovery process. The liver is of particular interest in ADME-Tox studies, as it is highly metabolically active and oral administrated drugs needs to pass the liver before reaching the systemic circulation. However, a dose of a drug that is efficacious and safe for one individual may be inefficacious or toxic, because of inter-individual variability. Therefore, it is important to investigate the ADME-Tox properties in a sufficiently large population. Investigations on ADME-Tox is usually done in in vitro cell models. Therefore, a variety of models to simulate liver functions have been developed and ranging from subcellular microsomes to complex 3D organoid cultures. This thesis investigates variability of ADME proteins in human liver tissue and in liver cell models.First, mass spectrometry based targeted proteomics was used to quantify ADME relevant proteins from 149 human liver samples. The observed inter-individual protein variability could not solely be explained by genotype. Therefore, a single transporter protein, the bile and drug transporting protein, NTCP, was investigate in detail. Non-genetic factors, e.g. smoking and alcohol consumption, and epigenetic factors such as DNA methylation, were found to contribute to the observed inter-individual variability of NTCP. Next, hepatocytes (PHH) were isolated from 54 human livers tissues and after which the hepatocytes where cryopreserved. The variable attachment efficiency of cryopreserved hepatocytes where investigated and an apoptosis inhibition protocol for restoration of attachment properties was developed. This protocol was also successfully applied to 3D cultured PHH spheroids resulting in increased ability to form 3D spheroids. The effect of culture conditions on the quality of the 3D cultures was also investigated. 3D PHH spheroids were formed and maintained in different, commonly used culture media. The spheroids were characterized by a variety of functional assays including global proteomics. The proteome analysis showed that while no epithelial to mesenchymal transitions was observed, 3D cultures maintained in fasting glucose and insulin levels resembling the in vivo situation showed a more liver-like phenotype with a high expression of ADME proteins and functional cytochrome P450 metabolism. Transporter kinetics were also investigated in the 3D cultured PHH. Finally, we investigated if global proteomics data from 56 human liver tissues could be deconvoluted to give information about the liver composition. The cell type proportions generated by deconvolution where similar to literature values. Liver samples that displayed deviating cell composition were identified. The deviating liver compositions were in agreement with clinical markers of inflammation in the patient´s blood samples and with altered extracellular matrix protein composition, comparable to that found in liver steatosis. In conclusion, this thesis have investigated variability in ADME proteins in human liver and in in vitro cultures of human hepatocytes, characterized cofounding factors for in vitro cultured hepatocytes and further extended drug disposition studies in 3D cultured hepatocytes.
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| 8. |
- Keemink, Janneke, et al.
(författare)
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Effect of Cryopreservation on Enzyme and Transporter Activities in Suspended and Sandwich Cultured Rat Hepatocytes
- 2018
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Ingår i: AAPS Journal. - : Springer Science and Business Media LLC. - 1550-7416. ; 20:2
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Tidskriftsartikel (refereegranskat)abstract
- Freshly-isolated rat hepatocytes are commonly used as tools for hepatic drug disposition. From an ethical point of view, it is important to maximize the use of isolated hepatocytes by cryopreservation. The present study compared overall hepatocyte functionality as well as activity of the organic anion transporting polypeptide (Oatp), multidrug resistance-associated protein 2 (Mrp2), and UDP-glucuronosyltransferase 1 (Ugt1), in in vitro models established with cryopreserved and freshly-isolated hepatocytes. A similar culture time-dependent decline in cellular functionality, as assessed by urea production, was observed in sandwich-cultured hepatocytes (SCH) obtained from freshly-isolated and cryopreserved cells. Concentration-dependent uptake kinetics of the Oatp substrate sodium fluorescein in suspended hepatocytes (SH) or SCH were not significantly affected by cryopreservation. Mrp2-mediated biliary excretion of 5 (and 6)-carboxy-2', 7'-dichlorofluorescein by SCH was assessed with semi-quantitative fluorescence imaging: biliary excretion index values increased between day 3 and day 4, but did not differ significantly between cryopreserved and freshly-isolated hepatocytes. Finally, telmisartan disposition was evaluated in SCH to simultaneously explore Oatp, Ugt1, and Mrp2 activity. In order to distinguish between the susceptibilities of the individual disposition pathways to cryopreservation, a mechanistic cellular disposition model was developed. Basolateral and canalicular efflux as well as glucuronidation of telmisartan were affected by cryopreservation. In contrast, the disposition parameters of telmisartan-glucuronide were not impacted by cryopreservation. Overall, the relative contribution of the rate-determining processes (uptake, metabolism, efflux) remained unaltered between cryopreserved and freshly-isolated hepatocytes, indicating that cryopreserved hepatocytes are a suitable alternative for freshly-isolated hepatocytes when studying these cellular disposition pathways.
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| 9. |
- Oorts, Marlies, et al.
(författare)
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Extra collagen overlay prolongs the differentiated phenotype in sandwich-cultured rat hepatocytes
- 2018
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Ingår i: Journal of pharmacological and toxicological methods. - : ELSEVIER SCIENCE INC. - 1056-8719 .- 1873-488X. ; 90, s. 31-38
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Sandwich-cultured rat hepatocytes (SCRH) have become an invaluable in vitro model to study hepatic drug disposition. SCRH are maintained between two layers of extracellular matrix. In this configuration, culture periods of 4 days are typically applicable. The aim of the present study was to modify conventional SCRH by applying an additional collagen overlay to prolong the hepatic phenotype in SCRH and thus to extend the applicability of the model.Methods: The cultures receiving an extra top layer ('SCRH-plus' cultures) were compared with the conventional SCRH by testing the morphology, cell functionality, metabolic capacity and Mrp2-activity.Results: In the SCRH-plus cultures, cell functionality, evaluated by measuring urea production, was increased from day 5 onwards, compared to conventional cultures. Furthermore, these cells retained the appearance of typical hepatocytes, in contrast with conventional sandwich cultures which showed rapid dedifferentiation. SCRH-plus exhibited significantly improved metabolic clearance mediated by cytochrome P450 3A compared to conventional SCRH whereas UDP-glucuronosyltransferase-mediated metabolism was unaffected. Both conventional SCRH and SCRH-plus showed extensive biliary networks at day 4 of culture. However, from day 4 onwards, a decline in biliary excretion index (BEI) was observed in the conventional SCRH, while BEI values in SCRH-plus cultures did not decrease until day 7.Discussion: The application of an extra top layer of collagen on the SCRH prolongs their useful life-span to 7 days. Therefore, SCRH-plus cultures will broaden the applications of SCRH in terms of long-term toxicity evaluation and when determining metabolism of low turnover compounds.
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